PORT ST. LUCIE – There couldn’t have been a bigger discrepancy between the two sessions. Not for Jose Reyes.

On Wednesday, the Mets’ 20-year-old wunderkind had to cut short his batting practice session after approximately 15 swings when he felt something in his strained right hamstring. It was a disturbing display, one that Reyes capped by slamming his bat disgustedly into a wooden blue rack.

Yesterday’s day at camp was 180 degrees different. After doing some light jogging and feeling fine, Reyes surprisingly decided to test the hamstring by hitting. The result? Not too shabby. He took approximately 40 swings, swatting line drives, hard grounders and deep blasts to all parts of the field and from both parts of the plate.

Best of all, Reyes, who wanted to see if he could pull the ball effectively, consistently ripped line drives over and past Mike Piazza at first base.

It was the ultimate feel-good display, and Reyes couldn’t stop grinning. But the thing is, the second baseman’s hamstring problems most assuredly remain. Essentially, Reyes, who has been out of action since March 14, is apparently having good days and bad days, and he likely remains headed to the 15-day disabled list.

“They’ve got a decision,” Reyes said of Mets brass.

Furthermore, the real issue that needs to be addressed is why Reyes is having so many hamstring issues. He’s strained the same one three times in the last 10 months. That can hardly be construed as coincidence.

“Hamstrings are very tricky things unfortunately. It’s just a matter of taking the proper time to let it heal and then figuring out how to prevent it. We’re working on that.”

When Reyes hurt himself a few weeks ago, GM Jim Duquette said that the Mets would consider altering his training regimen. Speaking in regard to hamstring issues in general and not Reyes specifically, Mackie Shilstone, a renowned sports performance manager who has worked with over 1000 professional athletes, said, “You really have to have a program that addresses the cause and not just the symptoms.”

So what is the cause of Reyes’ hamstring issues? Shilstone imagines that it’s one of three problems – a muscle imbalance between the ratio of the hamstring to the quad, pelvic instability or poor running mechanics (i.e., the hamstring may be tired and not appropriately trained to decelerate).

“It’s got to be one of them,” Shilstone said.

That Reyes would do so much physical work yesterday after Wednesday’s setback was surprising and prompted speculation that the Mets may be pushing Reyes too hard. But the prized second baseman insisted that while the Mets asked him to keep trying, he wanted to keep trying as well.